Question

Currently looking to extract data from 2 tables and insert into another.
Tables as follows (with example ideal data):

Table1
T1ID(PK)  T1Field1
301       2011-07-01
302       2011-07-01

Table2
T2ID(PK)  T2Field2  T2Field3  T2Field4
521       301       555       Apple
522       301       666       Pear


Table3 (new table)
T3Field1  T3Field2     T3Field3    T3Field4
301       2011-07-01   555         Apple
301       2011-07-01   666         Pear

Looking for the fewest and most efficient query’s to use in order to do the following:

1. Insert T1ID into T3Field1 + Insert T1Field1 into T3Field2

2. Update T3Field3 where T3Field1 = T2Field2 (for each) -*

Have simply used mysql insert for the first query. This NEEDS to be done first as it contains timestamp information.

*Attempted INNER JOIN here with no luck since there is a one-to-many and only the first row would get inserted.

I could select all of the results and then while loop / update within for each record but am trying to keep this as minimal as possible.

Just need a second opinion on the logic!

Answer 1

I tested the below code and it matches your ideal data. But, second row of Table1 is lost since there is no corresponding match for it in Table2

INSERT INTO Table3
SELECT 
Table1.T1ID AS T3Field1,
Table1.T1Field1 AS T3Field2,
Table2.T2Field3 AS T3Field3,
Table2.T2Field4 AS T3Field4
FROM Table1, Table2
WHERE
Table1.T1ID = Table2.T2field2